This invention relates to a method of and an apparatus for filtering a medium, particularly to an improvement in methods and apparatus for filtering a medium with a brush filter.
U.S. Pat. No. 4219,420, discloses an arrangement for and a process of filtering a contaminated medium. According to the patent, a plurality of fiber bundles are located on a support and extend within a filter housing in direction between an inlet and an outlet of the housing. The contaminated medium is introduced into the housing through the inlet in a direction towards the outlet. The contaminated particles are arrested by the fibers as they pass through the plurality of fiber bundles. In order to improve the "depth effect" of the fiber bundles, the fibers may have different lengths. The quality of the filtered medium depends on the density of the fiber bundles.
One of the disadvantages of the process and arrangement is that the density of the fiber bundles in the filtration process is the same as in the back-flushing process. In order to enhance the quality of the filtered medium, the density of the fibers must be increased, whereas the increase thereof within the arrangement will reduce the capacity of the arrangement to arrest contaminated particles and make the back-flushing process more difficult. For the process and the arrangement, therefore, the ability to enhance the quality of the filtered medium is limited and the flow speed of the contaminated medium in the arrangement is slow.